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Biomedical subjects

W F Dove

Publications and source records attributed to W F Dove.

At least 109 records · Page 6Linked to original sources

Genetic structure of the replication origin of bacteriophage lambda.

A fragment of bacteriophage lambda DNA produced by the restriction endonuclease Eco RI and extending from the immunity region to a point inside gene O is found to have a fully functional origin of replication. Seven ori- mutations of lambda cluster in a small region just to the left of the Eco RI cleavage site which defines the right end of this fragment. These mutations lie within gene O.

Chromosome Mapping↗

Anisomycin sensitive mutants of Physarum polycephalum isolated by cyst selection.

The haploid myxamoebae of Physarum polycephalum reversibly differentiate to form dormant microcysts under conditions of starvation. The thin-walled cysts can be selective recovered from a cell suspension which has been treated with the surfactant Triton X-100 to lyse amoeboid forms. Excystment, which is initiated by suspension in liquid medium, is inhibited by antibiotics which block protein synthesis. Cysts of drug resistant mutants excyst rapidly in media containing sufficient antibiotic to maintain drug sensitive strains in the encysted state. The selective survival of non-excysted cells following Triton X-100 treatment has been employed to enrich for drug sensitive mutants. Several anisomycin sensitive mutants have been isolated, one of which has been analysed genetically. The possible applications of this mutant enrichment technique are discussed.

Anisomycin↗

Viability of Physarum polycephalum spores and ploidy of plasmodial nuclei.

Amoebae of Physarum polycephalum carrying the mth mating-type allele may differentiate into plasmodia in the absence of mating. Such plasmodia are haploid and, upon sporulation, produce mainly inviable spores. We have asked whether the viable spores arise from meiotic or mitotic divisions. Using a microfluorometric measurement of the deoxyribonucleic acid content of individual nuclei, we found the fraction of viable spores to be correlated with the proportion of rare, diploid nuclei containing in the generally haploid plasmodium. When homozygous diploid plasmodia were created by heat shocking, spore viability increased dramatically. We suggest that viable spores are produced via meiosis in mth plasmodia, that the mth allele has no effect on sporulation per se, and that the normal source of viable haploid spores is a small fraction of diploid nuclei ubiquitous in haploid plasmodia.

Alleles↗